By The Pawline veterinary teamVeterinary-reviewed by Alastair Greenway, BVM&S MRCVS · 25 July 2026
Reference range · 10⁶/µL
5.58.5
Reference
5.5–8.5
Direction
Both unusually high and low values carry meaning.
This is the conventional reference interval. Your pet’s own report may print a slightly different range — always read the value against that. Sign in to see your pet’s value on this strip.
The red cell count is the number of oxygen-carrying cells in the blood, sitting alongside haematocrit and haemoglobin as a measure of oxygen-carrying capacity. A low value indicates anaemia; a high one usually means dehydration or overproduction — and it's read together with the red-cell indices.
The red blood cell count (RBC) is exactly that — the number of red cells per unit of blood. Together with the haematocrit (the proportion of blood that is red cells) and the haemoglobin (the oxygen-carrying pigment), it forms the trio that describes the blood's capacity to carry oxygen. In most situations these three move together and tell the same story, so the RBC count is rarely read in isolation.
The red cell count sits with haematocrit and haemoglobin as a measure of oxygen-carrying capacity. Low means anaemia; high, dehydration or overproduction.
Where the RBC count earns its keep is as the input to the red-cell indices — MCV, MCH and MCHC — which are calculated from it (and from haematocrit and haemoglobin) and which characterise what kind of anaemia is present.
Reading a low result
A low RBC count means anaemia, and the causes and work-up are exactly as for haematocrit: blood loss, red-cell destruction, or reduced production, sorted out with the reticulocyte count (young red cells) — a high reticulocyte count means a regenerative anaemia (loss or destruction, marrow responding), a low one a non-regenerative anaemia (a production problem). The indices then refine the picture.
Reading a high result
A high RBC count usually reflects dehydration (the cells concentrated by loss of plasma water) and corrects with fluids; less commonly, a genuine overproduction of red cells (polycythaemia) needs specific investigation. Hydration is assessed first.
In chronic disease
The RBC count is tracked alongside haematocrit and haemoglobin to follow anaemia in chronic disease — the slow decline of chronic kidney disease and chronic inflammation, and recovery with treatment. Its main added value in a longitudinal record is feeding the indices, which describe the character of the anaemia over time.
Cat vs dog
The RBC count is interpreted the same way in both species, running higher in cats than dogs (feline red cells are smaller and more numerous). Feline-specific rules apply to judging the reticulocyte response. In both, it is read with haematocrit, haemoglobin and the indices, never alone.
How it's measured
The RBC count is measured by the analyser as part of the CBC, reported in ×10⁶/µL (or ×10¹²/L). It is read alongside haematocrit, haemoglobin, the indices and the reticulocyte count. Read the value against your own report's range.
What to do next
A low RBC count is worked up as anaemia — the reticulocyte count to judge regeneration, and a search for loss, destruction or a production problem. A high count is usually addressed by correcting dehydration and rechecking. In every case it is read together with the rest of the red-cell picture rather than on its own.
Reference ranges reflect conventional laboratory intervals. Always interpret against your own lab's printed range and your veterinary surgeon's judgement. A brighter optimal band is shown only where a published guideline defines one, and it is cited.
This page is educational and is not a diagnosis. Lab results are interpreted in the full clinical context by your veterinary surgeon; a single value rarely tells the whole story.
